Copolymer of polar-substituted vinyl sulfides and alkyl acrylates



United States Patent 3,265,674 COPOLYMER 0F POLAR-SUBSTITUTED VINYLSULFIDES AND ALKYL ACRYLATES Dervin Leo Flowers, Palo Alto, Calif.,assignor to Shell Oil Company, New York, N.Y., a corporation of DelawareNo Drawing. Original application Oct. 10, 1960, Ser. No. 61,350, nowPatent No. 3,206,400, dated Sept. 14, 1965. Divided and this applicationMar. 26, 1965, Ser. No.

6 Claims. (Cl. zen-49.7

This patent application is a division of copending patent applicationSerial No. 61,350, filed October 10, 1960, and which matured into US.Patent 3,206,400 on September 14, 1965. The invention relates tooil-soluble polymeric compound having essentially a long linearhydrocarbon backbone chain and attached thereto in a uniform or randomfashion two essential polar-containing groups, one being a sulfur-freeester group represented by COOR, wherein R is a C preferably C alkylradical and the other polar group being a thioether-containing grouprepresented by -SR(-Y) wherein R is an omega-polar containing C alkylradical, the polar group (Y) being selected from the group consisting ofacidic-polar groups such as halogen, cyano, mercapto, hydroxyl, carboxylgroup, and preferably OH, SH, --CN and COOH group and n is at least 1.Polymeric compounds of this type should have a plurality of at least 8units selected from at least two of each such groups, and wherein R, R,Y and n are defined as above and the number of units is such that themolecular weight of the polymer ranges from at least 1,000 to about2,500,000, preferably from about 10,000 to about 600,000.

The polymeric compounds of the present invention are readily prepared byvarious means such as by copolymerizing, in the presence of a suitablecatalyst such as an azo catalyst, e.g., alpha,alpha-azo-diisobutyronitrile or an oxygen-yielding catalyst such asvarious organic peroxides, including aliphatic, aromatic, heterocyclicand acyl peroxides, such as diethyl peroxide, tertiary butylhydroperoxide, dibenzoyl peroxide, dimethylthienyl peroxide,dicyclohexyl peroxide, dilauroyl peroxide and urea peroxide. These arementioned by way of nonlimiting examples of suitable organic peroxides.Other catalysts include sodium bisulfite, diethyl sulfoxide, ammoniumpersulfate, alkali metal perborates, etc.

The sulfur-free polymerizable ester monomer is an ester of an acrylicacid, and an alkanol of from 8 to 20, preferably from 12 to 20 carbonatoms. Representative suitable alcohols are: n-lauryl, n-cetyl,n-stearyl, n-oleyl, and 2,2, 4,4,6,6-hexamethylheptyl alcohols. Examplesof suitable esters are n-lauryl acrylate, n-stearyl acrylate, n-laurylmethacrylate, n-cetyl methacrylate, n-stearyl methacrylate,2,2,4,4-tetramethyl lauryl methacrylate and their mixtures.

The other polymerizable monomer is a vinyl thioether (vinyl sulfide) [CHCHSR'-(Y)n] such as omegahydroxy or omega-alkoxy, oromega-carboxyl-substituted ethyl, propyl, butyl, 'amyl, heXyl, octyl,stearyl, phenyl, cyclohexyl, benzyl vinyl sulfides, preferablyomegahydroxyethyl vinyl sulfide, omega-hydroxyoctyl vinyl sulfide, vinylthioethyl glycidyl ether, omega-carboxyethyl vinyl sulfide and mixturesthereof.

The copolymers are prepared by polymerizing the two monomers in the molratio of 1:10 to 10: 1, preferably 1:3 to :1 of the sulfur-free acrylateester to the vinyl thioether (vinyl sulfide), respectively. The reactionis carried out in the presence of a polymerization initiator such as anazo or oxygen-yielding catalyst, in an inert solvent and at atemperature ranging from about 60 to about 150 C., preferably betweenand 125 C. for a period of from 2 to 48 hours, preferably from 8 to 35hours. The solvents are light liquid hydrocarbons such as benzene,xylene, toluene, light mineral oil, etc.

Various combinations of conditions may be employed to maintain themolecular weight within the desired range. Factors which exert aninfluence on the molecular weight of the polymer include the method ofpolymerization (e.g., polymerization in emulsion, suspension, solventsolution or bulk), the nature and concentration of the catalystemployed, the temperature, and nature and amount of the particularmonomers. When the polymerization is accomplished in solution, themolecular weight of the product will be lower when the dilution ishigher, e.g., when the proportion of solvent is greater. With the samecatalyst, the higher polymerization temperature tends to give lowermolecular weight polymers.

Under certain extreme conditions the detergent properties of copolymersof the present invention may be further improved and Wear inhibitionproperties imparted thereto, if necessary, by addition to the copolymer,based on the total monomer reactants, of from 5 to 30%, preferablybetween 10 and 20% of a polymerizable nitrogen-containing monomer,preferably polymerizable heterocyclic nitrogen-containing monomer whichmay be exemplified by 2-viny1pyridine, 3-vinylpyridine, 4-vinylpyridine,as well as the ring substituted alkyl derivatives thereof, e.g., 2methyl 5 vinyl-pyridine, 4 methyl 2-vinylpyridine, 5 ethyl 2vinylpyridine and 2 butyl 5 vinylpyridine, 2-methyl-viny1pyridine andthe like.

The following examples illustrate the preparation of suitable polymersfor use in oil compositions in accordance with the invention.

Example I A mixture of 5.4 mols of lauryl methacrylate, 3 mols ofstearyl methacrylate and 1 mol of hydroxyethyl vinyl sulfide was addedto a 50/50 mixture of benzene and light mineral oil diluent and themixture was reacted in the presence of 0.25% ditertbutyl peroxide at 120C. for about 24 hours. The copolymer lauryl methacrylate/ stearylmethacrylate/hydroxyethyl vinyl sulfide was recovered by precipitationfrom a benzene-alcohol mixture and had a molecular weight of400,000-500,000 and a sulfur content of 1.2% It had good solubility inlubricating oil and imparted thereto detergent and VI improvingproperties.

Example II A copolymer of stearyl methacrylate and vinyl thioethylglycidyl ether was prepared by the method of Example I, using thereactant monomers in a molar ratio of 2 to 1, respectively. Themolecular weight of the copolymer was around 420,000 and was oil-solubleand exhibited good detergent properties in lubricating oil.

Example III A copolymer of lauryl methacrylate and omega-hydroxy octylvinyl sulfide was prepared by the method of Example I in which the ratioof the reactants and conditions of the reaction were the same asdescribed in Example I. The polymeric product had a molecular weight of500,000, a sulfur content of 1.9% and was oil-soluble and exhibited gooddetergent and wear-inhibiting properties in lubricat ing oil.

Example IV A copolymer of stearyl methacrylate, lauryl methacrylate andhydroxyethyl vinyl sulfide in the mol ratio of 2:3:1 was prepared by theprocedure of Example I, except that the reaction temperature was C. andto the total monomer mixture was added 5% of Z-methyl- 5-vinylpyridine.The copolymer was oil-soluble and the molecular weight was around500,000 and exhibited good detergent properties.

The novel sulfide-containing polymers are effective as anti-wear anddetergents in liquid hydrocarbon compositions such as minerallubricating oil in the range of from about 0.001% to about preferablyfrom about 0.02% to about 5% by weight. The lubricating stock for thispurpose can be any natural or synthetic hydrocarbonaceous materialhaving lubricating properties. Thus, the base may be a hydrocarbon oilwithin a wide viscosity range, e.g., 100 SUS at 100 F. to 150 SUS at 210F. The hydrocarbon oils may be blended with fixed oils such as castoroil, lard oil and the like, and/or with synthetic lubricants such aspolymerized olefins, copolymers of alkylene glycols and oxides; organicesters of polybasic organic and inorganic acids, e.g., di-2-ethylhexylsebacate, dioctyl phthalate, trioctyl phosphate; polymerictetrahydrofuran; polyalkyl silicone polymers, e.g., dimethyl siliconepolymer and the like. In addition, the base can be gasoline, fuel oilsor greases.

The outstanding properties of oil compositions of this invention weredemonstrated when a mineral lubricating oil containing 2% of additive ofExample I (composition A) or 2% of additive of Example II (compositionB) were found to have VI values of about 140 as compared to 92 for theneat oil and in the caterpillar L-l engine test compositions A and Bgave clean engines with no evidence of wear or corrosion or sludgeformation, whereas a commercial detergent oil containing a metallicdetergent (sulfonate) tested under the same engine test conditionsresulted in severe corrosion and sludge formation in the engine.

The polymeric sulfides of this invention can be used to improve othertypes of compositions such as fuel oils, greases, hydraulic fluids ofthe oil, water-in-oil emulsion, insecticidal compositions, waxes, resinsand the like.

I claim as my invention:

1. As a new compound, a copolymer of C alkyl methacrylate and a vinylsulfide having the formula CHFCHSR'-Y where R is a C alkyl radical and Yis a polar radical selected from the groups consisting of OH and COOH,in the mol ratio of 1:10 to 10: 1, respectively, and such that the endproduct contains at least 8 units selected from the ester and vinylsulfide units and at least 2 of each group being present in the endproduct, said copolymer having a molecular weight of from about 1,000 toabout 2,500,000.

2. As a new compound, a copolymer of C alkyl methacrylate and a HOCalkyl vinyl sulfide, in the mol ratio of 1:10 to 10: 1, respectively,and such that the end product contains at least 8 units selected fromthe ester and vinyl sulfide units and at least 2 of each group beingpresent in the end product, said copolymer having a molecular weight offrom about 1,000 to about 2,500,000.

3. As a new compound, a copolymer of C alkyl methacrylate and a HOOCCalkyl vinyl sulfide in the mol ratio of 1:3 to 5: 1, respectively, andsuch that the end product contains at least 8 units selected from theester and vinyl sulfide unit and at least 2 of each group being presentin the end product, said copolymer having a molecular Weight from about10,000 to about 600,000.

4. As a new compound, a copolymer of stearyl methacrylate andhydroxyethyl vinyl sulfide in the mol ratio of 1:3 to 5:1, respectively,and such that the end product contains at least 8 units selected fromthe ester and vinyl sulfide unit and at least 2 of each group beingpresent in the end product, said copolymer having a molecular weightfrom about 10,000 to about 600,000.

5. As a new compound, a copolymer of stearyl methacrylate, laurylmethacrylate and hydroxyethyl vinyl sulfide in the mol ratio of 1:3 to 5:1, respectively, and such that the end product contains at least 8units selected from the ester and vinyl sulfide unit and at least 2 ofeach group being present in the end product, said copolymer having amolecular weight from about 10,000 to about 600,000.

6. As a new compound, a copolymer of stearyl methacrylate, laurylmethacrylate, 2-methyl-5-vinylpyridine and hydroxyethyl vinyl sulfide inthe mol ratio of 1:3 to 5: 1, respectively, and such that the endproduct contains at least 8 units selected from the ester and vinylsulfide unit and at least 2 of each group being present in the endproduct, said copolymer having a molecular weight from about 10,000 toabout 600,000.

No references cited.

JOSEPH L. SCHOFER, Primary Examiner.

D. K. DENENBERG, Assistant Examiner.

1. AS A NEW COMPOUND, A COPOLYMER OF C8-20 ALKYL METHACRYLATE AND AVINLY SULFIDE HAVING THE FORMULA CH2=CHS-R''-Y WHERE R'' IS A C2-18ALKYL RADICAL AND Y IS A POLAR RADICAL SELECTED FROM THE GROUPSCONSISTING OF -OH AND -COOH, IN THE MOL RATIO OF 1:10 TO 10:1,RESPECTIVELY, AND SUCH THAT THE END PRODUCT CONTAINS AT LEAST 8 UNITSSELECTED FROM THE ESTER AND VINYL SULFIDE UNITS AND AT LEAST 2 OF EACHGROUP BEING PRESENT IN THE END PRODUCT, SAID COPOLYMER HAVING AMOLECULAR WEIGHT OF FROM ABOUT 1,000 TO ABOUT 2,500,000.